USER MANUAL
STM 350 / STM 350U (STEPCODE DE OR HIGER)
TEMPERATURE AND HUMIDITY SENSOR MODULE
© 2019 EnOcean | www.enocean.com
F-710-017, V1.0
STM 350 / STM 350U User Manual | v1.4 | Dec 2019 | Page 8/14
3.1
Simplified device block diagram
3.2
Measurement and transmission timing
STM 350 and STM 350U wake up approximately once every 100 seconds to measure tem-
perature and humidity. The measured values are then compared against the last reported
(transmitted) values. If there is a significant change then the measured values are transmit-
ted immediately.
Significant change is defined as follows:
Temperature
The measured temperature deviates from the last reported temperature by more than
0.5 K
Humidity
The measured humidity deviates from the last reported humidity by more than 2%
r.h.
In absence of a significant change, a heartbeat telegram reporting the currently measured
values are transmitted for every 7 … 14 measurements (affected at random). The setup of
the transmission timing allows avoiding possible collisions with data packages of other
EnOcean transmitters as well as disturbances from the environment.
In addition, STM 350 and STM 350U reports the estimated energy level on their internal
energy storage element approximately every 100 measurements.
With each default transmission cycle, 3 identical sub-telegrams (secure mode 2) are trans-
mitted within 40ms. Transmission of a sub-telegram lasts approximately 1.2ms. The delay
between the three transmission bursts is affected at random.
